A new issue of this journal has just been published. To see abstracts of the papers it contains (with links through to the full papers) click here:
Selected papers from the latest issue:
A value-consistent dimensionality reduction model for electronic tongue data
01 February 2012, 22:20:07
Publication year: 2012
Source: Sensors and Actuators B: Chemical, Available online 31 January 2012
Hua-mao Gu, Shao-Ping Deng, Xun Wang, Jin-Qin Shi, Jian-Qiu Jin, ...
High-dimensional data are always a great challenge for post-processing. This paper proposed a new computational model for dimensionality reduction towards the huge data sampled from the multi-sensor array in voltammetric electronic tongue. It employs a linear superposition model of noise for a set of basis functions to describe the serial current responses of cross-sensitive multi-sensor array. And the coefficients of the basis function set, with a much lower dimensionality, are used as the reduced feature data for a sample. More importantly, the values of those coefficients show high consistency with the responses of electrodes, namely, larger currents measured may result in greater coefficient values, and vice versa.According to the theoretical analysis and practical results of the experiments, besides the value-consistency which is never supported by existing approaches, the proposed model also performs very well in the three key factors for evaluating an approach to dimensionality reduction (i.e. reduction rate, reconstruction error, and complexity): (1) strong ability in dimensionality reduction and feature preservation — the reduction rate reaches as high as circa 280 ∼ 420, and the average reconstruction error is circa 1% ∼ 5%; (2) linear time complexity — it's applicable to most huge datasets.
Source: Sensors and Actuators B: Chemical, Available online 31 January 2012
Hua-mao Gu, Shao-Ping Deng, Xun Wang, Jin-Qin Shi, Jian-Qiu Jin, ...
High-dimensional data are always a great challenge for post-processing. This paper proposed a new computational model for dimensionality reduction towards the huge data sampled from the multi-sensor array in voltammetric electronic tongue. It employs a linear superposition model of noise for a set of basis functions to describe the serial current responses of cross-sensitive multi-sensor array. And the coefficients of the basis function set, with a much lower dimensionality, are used as the reduced feature data for a sample. More importantly, the values of those coefficients show high consistency with the responses of electrodes, namely, larger currents measured may result in greater coefficient values, and vice versa.According to the theoretical analysis and practical results of the experiments, besides the value-consistency which is never supported by existing approaches, the proposed model also performs very well in the three key factors for evaluating an approach to dimensionality reduction (i.e. reduction rate, reconstruction error, and complexity): (1) strong ability in dimensionality reduction and feature preservation — the reduction rate reaches as high as circa 280 ∼ 420, and the average reconstruction error is circa 1% ∼ 5%; (2) linear time complexity — it's applicable to most huge datasets.
Automated detection of particle concentration and chemical reactions in EWOD devices
01 February 2012, 22:20:07
Publication year: 2012
Source: Sensors and Actuators B: Chemical, Available online 31 January 2012
M.J. Schertzer, R. Ben Mrad, P.E. Sullivan
Real-time measurement of electrical properties are used to perform the first real time detection of particle concentration and chemical reactions in electrowetting on dielectric devices without the need for optical access. For particle laden droplets, the change in both resistance and capacitance was found to be linear from zero to five-hundred particles with a resolution of approximately six particles for both measurements. Electrical properties were also measured for mixtures of alkaline phosphatase and p-Nitrophenyl Phosphate; reagents commonly used in immunoassays as the resultant chemical reaction produces a yellow precipitate. Experiments were performed with mixtures created off-chip and in droplet that were statically mixed on chip. The difference between the measured and expected capacitance was found to increase with the concentration of alkaline phosphatase and chemical reactions could be positively identified in mixtures made both on and off the chip. Real time measurements of reagents mixed in a four electrode electrowetting on dielectric mixer were also taken. In these experiments, chemical equilibrium was reached after approximately 20 cycles and the difference between the measured and expected capacitance was over 8.5 times greater than the experimental uncertainty.
Source: Sensors and Actuators B: Chemical, Available online 31 January 2012
M.J. Schertzer, R. Ben Mrad, P.E. Sullivan
Real-time measurement of electrical properties are used to perform the first real time detection of particle concentration and chemical reactions in electrowetting on dielectric devices without the need for optical access. For particle laden droplets, the change in both resistance and capacitance was found to be linear from zero to five-hundred particles with a resolution of approximately six particles for both measurements. Electrical properties were also measured for mixtures of alkaline phosphatase and p-Nitrophenyl Phosphate; reagents commonly used in immunoassays as the resultant chemical reaction produces a yellow precipitate. Experiments were performed with mixtures created off-chip and in droplet that were statically mixed on chip. The difference between the measured and expected capacitance was found to increase with the concentration of alkaline phosphatase and chemical reactions could be positively identified in mixtures made both on and off the chip. Real time measurements of reagents mixed in a four electrode electrowetting on dielectric mixer were also taken. In these experiments, chemical equilibrium was reached after approximately 20 cycles and the difference between the measured and expected capacitance was over 8.5 times greater than the experimental uncertainty.
Rapid determination of pesticide mixtures using disposable biosensors based on genetically modified enzymes and artificial neural networks
01 February 2012, 22:20:07
Publication year: 2012
Source: Sensors and Actuators B: Chemical, Available online 31 January 2012
Gustavo A. Alonso, Georges Istamboulie, Thierry Noguer, Jean-Louis Marty, Roberto Muñoz
We present a one-step inhibition biosensor method that can be used to determine mixtures of three organophosphorus compounds. We propose to calculate the rate of irreversible inactivation of the enzyme (kp) to demonstrate the direct relationship between enzymatic biosensors and Chlorpyriphos-oxon (CPO), Chlorfenvinphos (CFV) and Azinphos-methyl oxon (AZMO) insecticides. The array of biosensors was designed using only two acetylcholinesterases fromDrosophila melanogaster(wild-type and genetically modified). We used the values the slope of inhibitionsmifrom an array of biosensors and an artificial neural network to solve mixtures of CPO, CFV and AZMO insecticides The errors were low between the obtained and expected values for a set of 20 external test samples.
Source: Sensors and Actuators B: Chemical, Available online 31 January 2012
Gustavo A. Alonso, Georges Istamboulie, Thierry Noguer, Jean-Louis Marty, Roberto Muñoz
We present a one-step inhibition biosensor method that can be used to determine mixtures of three organophosphorus compounds. We propose to calculate the rate of irreversible inactivation of the enzyme (kp) to demonstrate the direct relationship between enzymatic biosensors and Chlorpyriphos-oxon (CPO), Chlorfenvinphos (CFV) and Azinphos-methyl oxon (AZMO) insecticides. The array of biosensors was designed using only two acetylcholinesterases fromDrosophila melanogaster(wild-type and genetically modified). We used the values the slope of inhibitionsmifrom an array of biosensors and an artificial neural network to solve mixtures of CPO, CFV and AZMO insecticides The errors were low between the obtained and expected values for a set of 20 external test samples.
Nano bimetallic Ag/Pt system as efficient opto and electrochemical sensing platform towards adenine
01 February 2012, 22:20:07
Publication year: 2012
Source: Sensors and Actuators B: Chemical, Available online 31 January 2012
B. Karthikeyan, M. Murugavelu
Ag–Pt bimetallic nanoparticles (BNPs) were prepared by chemical reduction method. The obtained BNPs were examined by UV–Vis spectroscopy, fluorescence, FT-IR analysis, field-emission scanning electron microscopy (FESEM), Energy-dispersive X-ray analyses (EDX), XRD, transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HRTEM). The combined electrochemical and optical experiments indicated that Ag-Pt BNP system can be used as efficient opto and electrochemical sensing platform towards adenine.
Source: Sensors and Actuators B: Chemical, Available online 31 January 2012
B. Karthikeyan, M. Murugavelu
Ag–Pt bimetallic nanoparticles (BNPs) were prepared by chemical reduction method. The obtained BNPs were examined by UV–Vis spectroscopy, fluorescence, FT-IR analysis, field-emission scanning electron microscopy (FESEM), Energy-dispersive X-ray analyses (EDX), XRD, transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HRTEM). The combined electrochemical and optical experiments indicated that Ag-Pt BNP system can be used as efficient opto and electrochemical sensing platform towards adenine.
Myoglobin within graphene oxide sheets and Nafion composite films as highly sensitive biosensor
01 February 2012, 22:20:07
Publication year: 2012
Source: Sensors and Actuators B: Chemical, Available online 31 January 2012
Changchun Guo, Hong Sun, X.S. Zhao
A highly sensitive biosensor was fabricated by incorporating myoglobin (Mb) within graphene oxide (GO) sheets and Nafion composite films. The stable composite Mb-GO-Nafion films were characterized by electrochemistry, scanning electron microscope, Fourier transform infrared spectroscopy and UV-vis spectroscopy. It was found that Mb in Mb-GO-Nafion films retained its secondary structure similar to its native states. Cyclic voltammetry of Mb-GO-Nafion films showed a pair of well defined, quasi-reversible peaks at about -0.312 V vs saturated calomel electrode (SCE) at pH 5.5, corresponding to direct electron transfer (DET) between Mb and the glassy carbon electrode. Electrochemical parameter of Mb in Mb-GO-Nafion film such as apparent heterogeneous electron transfer rate constant (ks) and formal potential (E′) were obtained. The dependence ofEon solution pH indicated that the DET reaction of Mb was coupled with proton transfer. Mb in the films displayed good electrocatalytic activities towards various substrates such as hydrogen peroxide, nitrite and oxygen, indicating that the composite films have potential applications in fabricating novel biosensors without using mediators.
Source: Sensors and Actuators B: Chemical, Available online 31 January 2012
Changchun Guo, Hong Sun, X.S. Zhao
A highly sensitive biosensor was fabricated by incorporating myoglobin (Mb) within graphene oxide (GO) sheets and Nafion composite films. The stable composite Mb-GO-Nafion films were characterized by electrochemistry, scanning electron microscope, Fourier transform infrared spectroscopy and UV-vis spectroscopy. It was found that Mb in Mb-GO-Nafion films retained its secondary structure similar to its native states. Cyclic voltammetry of Mb-GO-Nafion films showed a pair of well defined, quasi-reversible peaks at about -0.312 V vs saturated calomel electrode (SCE) at pH 5.5, corresponding to direct electron transfer (DET) between Mb and the glassy carbon electrode. Electrochemical parameter of Mb in Mb-GO-Nafion film such as apparent heterogeneous electron transfer rate constant (ks) and formal potential (E′) were obtained. The dependence ofEon solution pH indicated that the DET reaction of Mb was coupled with proton transfer. Mb in the films displayed good electrocatalytic activities towards various substrates such as hydrogen peroxide, nitrite and oxygen, indicating that the composite films have potential applications in fabricating novel biosensors without using mediators.
Immobilization of Glucose Oxidase by Langmuir-Blodgett Technique for Fabrication of Glucose Biosensors: Headgroup Effects of Template Monolayers
01 February 2012, 22:20:07
Publication year: 2012
Source: Sensors and Actuators B: Chemical, Available online 31 January 2012
Ke-Hsuan Wang, Mei-Jywan Syu, Chien-Hsiang Chang, Yuh-Lang Lee
Glucose oxidase (GOx) molecules were adsorbed from aqueous solution onto template monolayer of octadecylamine (ODA) or stearic acid (SA) at the air/liquid interface. The effects of the template layers on the GOx adsorption and the characteristics of the mixed template/GOx monolayers are studied. The monolayers at the air/liquid interface were then transferred onto Pt substrates to prepare GOx Langmuir-Blodgett (LB) films for glucose sensing study. The results show that the SA/GOx monolayer has a pressure-area isotherm resembles that of a SA monolayer, indicating that only a small amount of GOx was incorporated in the mixed film. On the contrary, the ODA/GOx monolayers exhibit high expanded and high compressible characteristics, attributed to the high incorporation amount of GOx induced by the electrostatic interaction between ODA and GOx. The glucose sensing experiments demonstrate that the ODA/GOx LB films have much better performance than SA/GOx films in terms of current sensitivity and current responding rate. Furthermore, an ODA/GOx film prepared after approaching the second equilibrium stage of GOx adsorption (8 h adsorption) shows a better performance than that prepared at the first equilibrium stage. Good linear relationship between response current and glucose concentration was obtained for the GOx-LB films between 0.1 and 5 mM.
Source: Sensors and Actuators B: Chemical, Available online 31 January 2012
Ke-Hsuan Wang, Mei-Jywan Syu, Chien-Hsiang Chang, Yuh-Lang Lee
Glucose oxidase (GOx) molecules were adsorbed from aqueous solution onto template monolayer of octadecylamine (ODA) or stearic acid (SA) at the air/liquid interface. The effects of the template layers on the GOx adsorption and the characteristics of the mixed template/GOx monolayers are studied. The monolayers at the air/liquid interface were then transferred onto Pt substrates to prepare GOx Langmuir-Blodgett (LB) films for glucose sensing study. The results show that the SA/GOx monolayer has a pressure-area isotherm resembles that of a SA monolayer, indicating that only a small amount of GOx was incorporated in the mixed film. On the contrary, the ODA/GOx monolayers exhibit high expanded and high compressible characteristics, attributed to the high incorporation amount of GOx induced by the electrostatic interaction between ODA and GOx. The glucose sensing experiments demonstrate that the ODA/GOx LB films have much better performance than SA/GOx films in terms of current sensitivity and current responding rate. Furthermore, an ODA/GOx film prepared after approaching the second equilibrium stage of GOx adsorption (8 h adsorption) shows a better performance than that prepared at the first equilibrium stage. Good linear relationship between response current and glucose concentration was obtained for the GOx-LB films between 0.1 and 5 mM.
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